The most effective NDT method for locating surface cracks in ferromagnetic materials is:

The most effective NDT method for locating surface cracks in ferromagnetic materials is:

• c) Magnetic particle testing

Magnetic particle testing is specifically designed for detecting surface and near-surface discontinuities in ferromagnetic materials. The method relies on the principle that when a ferromagnetic material is magnetized, any surface or near-surface discontinuity will cause a leakage field. Magnetic particles applied to the surface are attracted to this leakage field, forming an indication that reveals the discontinuity. The note provided in the image also confirms its effectiveness for detecting surface and near-surface discontinuities in ferromagnetic materials.